Apparatus for explanting a dental implant from a human or animal bone

ABSTRACT

Example apparatus for explanting a dental implant from a human or animal bone are disclosed herein. In one example, the apparatus includes a trephine bur on an end side of which there is formed a bur bit. In one or more examples, an apparatus by which dental implants can be drilled out accurately is achieved by a guide pin that can be attached to the dental implant and by a guide element attached to the trephine bur, said guide element cooperating with the guide pin so that the trephine bur is guided in the axial direction of the guide pin.

RELATED APPLICATIONS

This patent is a continuation of U.S. patent application Ser. No.12/565,539, which was filed on Sep. 23, 2009 and claim priority toGerman Patent Application No. DE 10 2008 049 012.1, which was filed onSep. 25, 2008, both of which are hereby incorporated by reference intheir entireties.

TECHNICAL FIELD

The present disclosure relates to dental implants and, moreparticularly, to apparatus for explanting a dental implant from a humanor animal bone.

BACKGROUND

To replace missing teeth, it belongs to prior art to implant into thejaw bone artificial dental implants made from titanium, ceramics or fromanother suited material. Sometimes however it is also necessary toremove again an existing dental implant such as when there is aninflammation or sleeping implant. In this case, the dental implant canbe drilled out again, using a hollow bur such as a trephine bur theinner diameter of which is only slightly larger than the largest outerdiameter of the dental implant. Then, this trephine bur is at first heldonto the dental implant, relying on the visual judgment of the doctor,in such a manner that the trephine bur forms a surrounding grip, atleast rudimentarily, around the upper part of the dental implant. Duringdrilling, the trephine bur is then guided by the dental implant.However, sometimes, the drilling occurs slantwise so that, in somecases, the dental implant is even cut into pieces, which involves acomplicated surgical intervention in order to remove the rests of thedental implant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a first example of an apparatus inaccordance with the teachings of the present invention together with asectional view of a dental implant in a jaw bone prior to drilling.

FIG. 2 shows the apparatus shown in FIG. 1 directly before penetrationof the trephine bur into the jaw bone.

FIG. 3 shows the apparatus shown in FIG. 1 upon completion of thedrilling operation.

FIG. 4 shows the apparatus shown in FIG. 1 with the trephine burremoved.

FIG. 5 shows a sectional side view of a second example of an apparatusin accordance with the teachings of the present invention together witha sectional view of a dental implant in a jaw bone before beginning withthe drilling operation.

FIG. 6 shows the apparatus shown in FIG. 5 directly before penetrationof the trephine bur into the jaw bone.

FIG. 7 shows the apparatus shown in FIG. 5 upon completion of thedrilling operation.

FIG. 8 shows the apparatus shown in FIG. 5 with the trephine burremoved.

FIG. 9 shows a sectional side view of a third example of an apparatus inaccordance with the teachings of the present invention together with asectional view of a dental implant in a jaw bone prior to drilling.

FIG. 9 a shows a sectional top view of the apparatus shown in FIG. 9,taken along section line IXa to IXa in FIG. 9.

FIG. 9 b shows a sectional top view of the apparatus shown in FIG. 9,taken along section line IXb bis IXb in FIG. 9.

FIG. 10 shows the apparatus shown in FIG. 9 upon completion of thedrilling operation.

FIG. 11 shows a sectional side view of a fourth example of an apparatusin accordance with the teachings of the present invention together witha sectional view of a dental implant in a jaw bone before beginning withthe drilling operation.

FIG. 11 a is a side view of the guide cylinder of the apparatus shown inFIG. 11.

FIG. 12 shows the apparatus shown in FIG. 11 upon completion of thedrilling operation.

DETAILED DESCRIPTION

In the FIGS. 1 through 4 there is shown a first example apparatus inaccordance with the teachings of the present invention at differentinstants in time. This example apparatus incorporates a hollowcylindrical trephine bur 1 on the end side of which there is formed abur bit 2. Opposite the bur bit 2 a bur receiving mount 3 is attached tothe trephine bur 1, said bur receiving mount serving to couple thetrephine bur 1 to a corresponding drive which has not been illustratedin closer detail herein. In the interior of the trephine bur 1 a guideelement 5 is retained through four webs 4. This guide element 5 isconfigured to be hollow cylindrical and is disposed coaxially withrespect to the trephine bur 1.

A dental implant 7 is implanted in the jaw bone 6 and a guide pin 8 isplaced in this dental implant 7. The guide pin 8 is disposed coaxialwith the dental implant 7, i.e., the virtual longitudinal axis of theguide pin 8 and the virtual longitudinal axis of the dental implant 7are identical or substantially identical.

In one example, the distance A between the end side of the trephine bur1 and the lower end side of the guide element 5 is at least equal to thelength of the dental implant 7 whilst the guide pin 8 is considerablylonger than the distance A so that the guide pin 8 already extends intothe guide element 5 whilst the trephine bur 1 still fits against the jawbone 6.

In another example that has not been illustrated herein, the distance Asubstantially corresponds to the length of the dental implant 7.

One example way in which such a drilling operation is performed will bedescribed in detail herein after.

At first, the guide pin 8 is placed into the dental implant 7 (FIG. 1)so that the guide pin 8 is disposed coaxial, or substantially coaxial,with the dental implant 7. Then, the trephine bur 1, with the guideelement 5 disposed coaxially therein, is guided over the guide pin 8 sothat the guide pin 8 enters into the interior of the guide element 5(FIG. 2). Thanks to the cooperation between guide pin 8 and guideelement 5, the trephine drill 1 is oriented coaxial with the dentalimplant 7. If drilling is now performed, the trephine bur 1 is reliablyguided coaxial with the dental implant 7 thanks to the cooperationbetween guide pin 8 and guide element 5 (FIG. 3). Upon completion of thedrilling operation, the trephine bur 1 is removed from the jaw bone 6.At last, the dental implant 7 is removed, the bone on the end side ofthe dental implant 7 having to be detached first. In the first exampleshown in the FIGS. 1 through 4, the clear diameter of the bur 1 isapproximately 1 millimeters (mm) to 6 mm, in one example preferably 3 mmlarger than the largest outer diameter of the dental implant 7. As aresult, the dental implant 7 can be removed together with the bonesubstance 6 surrounding the implant. Such a dental implant 7 can then beimplanted somewhere else, for example at a place with but little bonesubstance.

The second example shown in the FIGS. 5 through 8 differs from the firstexample by the fact that here the diameter of the trephine bur 11 is butslightly larger than the largest outer diameter of the dental implant.As a result, the dental implant can be drilled out accurately, meaningwith a minimum of bone matter. Such a trephine bur 11 is typicallychosen when the implant is not intended for further use.

In the FIGS. 9 through 10, there is shown a third example. According tothe third example, an implant 27 is embedded in a jaw bone 26, a guidepin 28 being placed into the implant 27. Above the trephine bur 21 thereis mounted a hollow cylindrical guide element 25 which is retained onthe trephine bur 21 through four webs 24. This trephine bur 21 also hasa bur bit 22 on its end side.

Unlike the first example shown in the FIGS. 1 through 4, the guideelement 25 is here disposed outside of the trephine bur 21, but is alsoconfigured to be hollow cylindrical for reception of the guide pin 28.For the rest of the description, this third example substantiallycorresponds to the first example, which is shown in the FIGS. 1 through4.

In the fourth example shown in the FIGS. 11 through 12, and unlike inthe first three examples, a commercially available trephine bur 32 isused, which is driven through a bur reception mount 33 and also has abur bit 32. In this example, a guide cylinder 35, which can be placedinto the implant 37, is utilized instead of the guide pin. This guidecylinder 35 can be fixed in the implant 37 through a receiving portion,here a thread.

Above the implant 37, two guide surfaces 39 and 39′ are configured onthe guide cylinder 35. In the region of these guide surfaces 39 and 39′,the guide cylinder 35 is configured to be cylindrical whilst the guidecylinder 35 comprises, in the region between the guide surfaces 39 and39′, a groove 40 so that the guide surfaces 39 and 39′ are spaced apartby said groove 40. In the region of the guide surfaces 39 and 39′, theouter diameter of the guide element 35 substantially corresponds to theclear inner diameter of the trephine bur 31 so that the guide cylinder35 can be introduced into the trephine bur 31, guiding said bur coaxialwith the implant 37 during the drilling operation.

If the physician uses a trephine bur and a guide cylinder the diametersof which correspond to the diameter of the implant, the implant isdrilled out without bone substance. If, by contrast, it uses a trephinebur and a guide cylinder whose diameter is larger than the implant, bonesubstance is drilled out, together with the implant, and said bonesubstance can be implanted again somewhere else.

Each implant manufacturer gives the receptacle for its implant anindividual shape. It may be, as shown herein, a thread, but it may alsobe of another shape. It is understood that the fastening means of theguide pin or of the guide cylinder is configured according to thereceptacle of the implant and needs not be a thread like in theseexamples.

In another example that has not been illustrated herein, the trephinedrill may be equipped with an ultrasonic cutting apparatus or with apiezo cutting apparatus.

In view of the foregoing, the examples described herein may provide anapparatus of the type mentioned herein above by means of which dentalimplants can be drilled out in an axially parallel manner. Theinventions, as defined by the claims appended hereto, provide atechnical solution to facilitate the results achieved by the examples.

One or more of the foregoing examples are advantageous in that, throughthe cooperation of guide pin and guide element or of guide cylinder andtrephine bur, one realizes a reliable guidance of the trephine bur sothat said bur can penetrate into the bone, guided so as to be coaxialwith the dental implant. One thus achieves that the dental implant isnot damaged and can be readily and completely removed.

Another advantage realized by one or more of the foregoing examples isthat, by drilling around the implant in an axially parallel manner, onealso burs out a certain amount of bone substance, the bone substanceabout the implant being of uniform thickness. Depending on the size ofthe trephine bur, the belt of bone substance around the implant can bemore or less thick.

In a preferred example, the guide element is configured to be hollowcylindrical, the clear width of the guide element being chosen tocorrespond to the diameter of the guide pin. The advantage thereof isthat the guide element attached to the trephine bur receives the guidepin attached to the dental implant in order to thus realize a reliableguidance of the trephine bur. It is understood that the clear width ofthe guide element is configured to be so much larger than the diameterof the guide pin that the guide pin can be introduced readily into theguide element whilst concurrently the clear width of the guide elementwill not be chosen to be much larger than the diameter of the guide pinso that the guide pin can be guided in the guide element with only asmall clearance. This applies in analogous fashion for the guidecylinder and the trephine bur.

It has proved advantageous to, in some examples, coaxially attach theguide element to the trephine bur and to also coaxially attach the guidepin in the dental implant. One thus achieves that the trephine bur isguided coaxial with the dental implant so that the distance between thedental implant and the interior of the trephine bur is approximatelyequal over the circumference of the dental implant.

In a preferred example the guide element is retained on the trephine burthrough three to eight, preferably through four webs. Thanks to thesewebs, the trephine bur is open toward the top so that material possiblyneeded during the intervention may be fed or other material may beevacuated as a result thereof.

In another preferred example, the guide pin already extends into theguide element when the trephine bur still fits against the bone. Thisoffers the advantage that a guide of the trephine bur is already coaxialwith the dental implant before the actual drilling begins so that it isno longer necessary to correct the orientation during the drillingoperation.

In still another preferred example, the guide element is spaced adistance from the bur bit that is equal to the length of the dentalimplant. The advantage thereof is that the trephine bur can penetrate sofar into the bone until it reaches the lower end of the dental implantso that the dental implant can be completely drilled out.

In another preferred example, the guide element is integral with thetrephine bur, which contributes to simplify the manufacturing of thetrephine bur.

In another, particularly preferred example, a guide cylinder is usedinstead of the guide pin, the outer diameter of said guide cylindercorresponding to the clear inner diameter of the trephine bur. Thisoffers the advantage that a commercially available trephine bur can beused while still achieving a coaxial guidance of the trephine bur.

In an advantageous developed implementation, preferably two (at leastone however) guide surfaces are formed on the circumference of the guidecylinder, said guide surfaces serving to bring the guide cylinder toabut in the interior of the trephine bur and to guide it. These guidesurfaces are spaced apart in order to avoid canting.

This patent application makes reference to, incorporates the same hereinby reference, and claims all benefits accruing under 35 U.S.C. §119 froman application for patent filed in the German Patent Office on Sep. 25,2008, and there assigned Serial No. DE 10 2008 049 012.1.

Further advantages of the example apparatus constructed in accordancewith the invention described herein will become apparent in the appendeddrawings and the foregoing description of examples thereof Likewise, theinvention lies in each and every novel feature or combination offeatures mentioned above or described herein after. The examplesprovided are not intended to limit the scope of the invention in anymanner. Although certain example apparatus, methods, and articles ofmanufacture are described herein, other implementations are possible.The scope of coverage of this patent is not limited to the specificexamples described herein. On the contrary, this patent covers allapparatus, methods, and articles of manufacture falling within the scopeof the invention.

1. An apparatus comprising: a trephine bur; a bur bit on an end of thetrephine bur; a guide pin attachable to a dental implant; and a guideelement attached to the trephine bur, the guide element cooperating withthe guide pin to guide the trephine bur in an axial direction of theguide pin.
 2. The apparatus of claim 1, wherein the guide element is ahollow cylinder having a width substantially corresponding to a diameterof the guide pin.
 3. The apparatus of claim 1 further comprising aplurality of webs to retain the guide element in the trephine bur. 4.The apparatus of claim 3, wherein the plurality of webs comprises threeto eight webs.
 5. The apparatus of claim 1, wherein the guide pin is toextend into the guide element when the trephine bur fits against a jawbone.
 6. The apparatus of claim 1, wherein a distance between the guideelements and the bur bit substantially corresponds to a length of thedental implant.
 7. The apparatus of claim 1, wherein a distance betweenthe guide element and the bur bit corresponds at least to a length ofthe dental implant.
 8. An apparatus comprising: a trephine bur; a burbit on an end of the trephine bur; and a guide cylinder attachable to adental implant, the guide cylinder comprising a first cylindrical guidesurface having a first outer diameter corresponding an inner diameter ofthe trephine bur.
 9. The apparatus of claim 8, the guide cylinderfurther comprising a second guide surface spaced axially from the firstguide surface.
 10. The apparatus of claim 9, the guide cylinder furthercomprising a groove between the first and second cylindrical guidesurfaces.
 11. The apparatus of claim 10, wherein the groove is rounded.12. The apparatus of claim 9, wherein the second guide surface has asecond outer diameter substantially equal to the first outer diameter.13. The apparatus of claim 8, wherein the guide cylinder is to be fixedin the dental implant.
 14. The apparatus of claim 8, wherein the guidecylinder comprises an extension to penetrate the dental implant.
 15. Theapparatus of claim 8, wherein an interior wall of the trephine bur is toengage the guide cylinder.
 16. The apparatus of claim 8 furthercomprising a bur reception mount to drive the trephine bur.
 17. Theapparatus of claim 8 further comprising a thread to fasten the guidecylinder to the implant.
 18. The apparatus of claim 8, wherein the innerdiameter of the trephine bur corresponds to a diameter of the implant.19. The apparatus of claim 8, wherein the inner diameter of the trephinebut is larger than a diameter of the implant.
 20. The apparatus of claim8, wherein the guide cylinder has a lower end that has a diametersubstantially corresponding to a diameter of an adjacent end of theimplant.